Methods for slitting foiled metal sheets have become known, for example, by the so-called “TRUMPF foil slitting tool”. Foiled metal sheets are provided with a protective foil which protects the metal sheet from damage during processing, storage and handling and which in most cases is only removed immediately before the metal sheet is processed further.
The TRUMPF foil slitting tool has a ball which is rotatably mounted in a die and which is moved on a foiled metal sheet with a rolling movement and thereby slits the foil without leaving scratches or marks on the metal sheet. More precisely, the ball is set onto the surface of the metal sheet during processing, whereby the tip of the ball pierces the foil and then rolls on the metal sheet as it is moved over the metal sheet. In this manner, the foil is cut simply and quickly along the path that is travelled. In particular, separate areas or segments can be separated on the foil by means of the foil slitting tool and can then be removed from the metal sheet manually. However, the slitting gap produced by the foil slitting tool is naturally very narrow and therefore does not facilitate the manual detachment of the foil or of a foil segment.
Also known as removal aids for the detachment of the foil are acute-angled “foil marking tools”, for example in the form of a pointed brass needle. The brass needle is softer than the metal sheet, so that there are no scratches on the metal sheet, but the brass needle becomes worn and must be replaced often. If scratches on the sheet are not important, a harder tip can also be used, which lasts longer but scratches the metal sheet.